A digital universal timer is known which is operable in several different modes or functions, including (1) start-stop with total elapsed time, (2) start-stop with accumulative event time, (3) split, (4) sequential with total elapsed time, (5) rally with total elapsed time, and others not relevant to this invention. Such a timer is embodied in a monolithic MOS integrated circuit available from National Semiconductor Corporation of Santa Clara, California and is identified by the alphanumeric designation MM5865.
In another timer, namely the Cronus Model M-D Dual Action Timer, simultaneous displays in Split (.SIGMA.) and Taylor (.DELTA.) modes are provided.
It is further known to combine timers in a single package whereby a plurality of timers can be started simultaneously and subsequently operated individually in order to time two or more participants in a single study, such as competitors in a race. Each timer is capable of dual mode operation to provide indications of lap (elapsed) times and race (total) times for each participant. Such a system is disclosed in U.S. Pat. No. 3,889,103 issued June 10, 1975 to Lewis B. Russell and William F. Kelly.
Further, it is known in a data evaluation system to compute the sum of sigma squared of input data for purposes other than time study (Micka U.S. Pat. No. 3,908,118, issued Sept. 23, 1975).
Lastly, it has been recognized that the realiability of a particular statistical study may be determined by mathematical algorithms set forth in an article entitled "How Many Readings for a Time Study" by M. E. Mundel which appeared in "Modern Management" for August, 1949, at pages 21 and 22.